Archives of Microbiology

, Volume 195, Issue 1, pp 51–61

The mitochondrial respiratory chain of Rhizopus stolonifer (Ehrenb.:Fr.) Vuill

Authors

  • Leobarda Robles-Martínez
    • Departamento de Microbiología, Escuela Nacional de Ciencias BiológicasInstituto Politécnico Nacional
  • María Guadalupe Guerra-Sánchez
    • Departamento de Microbiología, Escuela Nacional de Ciencias BiológicasInstituto Politécnico Nacional
  • Oscar Flores-Herrera
    • Departamento de Bioquímica, Facultad de MedicinaUniversidad Nacional Autónoma de México
  • Ana Niurka Hernández-Lauzardo
    • CEPROBI, Instituto Politécnico Nacional
  • Miguel Gerardo Velázquez-Del Valle
    • CEPROBI, Instituto Politécnico Nacional
    • Departamento de Bioquímica, Facultad de MedicinaUniversidad Nacional Autónoma de México
Original Paper

DOI: 10.1007/s00203-012-0845-7

Cite this article as:
Robles-Martínez, L., Guerra-Sánchez, M.G., Flores-Herrera, O. et al. Arch Microbiol (2013) 195: 51. doi:10.1007/s00203-012-0845-7

Abstract

Rhizopus stolonifer (Ehrenb.:Fr.) Vuill mitochondria contain the complete system for oxidative phosphorylation, formed by the classical components of the electron transport chain (complexes I, II, III, and IV) and the F1F0-ATP synthase (complex V). Using the native gel electrophoresis, we have shown the existence of supramolecular associations of the respiratory complexes. The composition and stoichiometry of the oxidative phosphorylation complexes were similar to those found in other organisms. Additionally, two alternative routes for the oxidation of cytosolic NADH were identified: the alternative NADH dehydrogenase and the glycerol-3-phosphate shuttles. Residual respiratory activity after inhibition of complex IV by cyanide was inhibited by low concentrations of n-octyl gallate, indicating the presence of an alternative oxidase. The K0.5 for the respiratory substrates NADH, succinate, and glycerol-3-phosphate in permeabilized cells was higher than in isolated mitochondria, suggesting that interactions of mitochondria with other cellular elements might be important for the function of this organelle.

Keywords

Oxidative phosphorylationF1F0-ATP synthaseRespiratory supercomplexesNADH dehydrogenaseGlycerol-3-phosphate shuttle

Supplementary material

203_2012_845_MOESM1_ESM.jpg (101 kb)
Solubilization of respiratory complexes by DDM. Increased concentrations of DDM were used to release the complexes from Rhizopus stolonifer mitochondria. (A) Blue native gel stained with Coomassie blue and (B) NADH dehydrogenase activity. (JPEG 100 kb)
203_2012_845_MOESM2_ESM.jpg (160 kb)
Solubilization of respiratory supercomplexes by digitonin. Increased concentrations of digitonin were used to release the supercomplexes from Rhizopus stolonifer mitochondria. (A) Blue native gel stained with Coomassie blue and (B) NADH dehydrogenase activity. (JPEG 159 kb)
203_2012_845_MOESM3_ESM.jpg (169 kb)
Respiratory activity and sensitivity by permeabilized Rhizopus stolonifer cells. Cells were permeabilized by digitonin (0.02%) in the absences of any substrate or inhibitor. Oxygen uptake was stimulated by exogenous 384 μM NADH in the (A) absence or (B) presence of 3 μM rotenone, respectively. The respiration was inhibited by 1 mM KCN. Additions are indicated by arrows. Number on the trace represents the rate of oxygen uptake in nmol O2 min-1 (mg cells)-1. Oximetric experiments were performed at 25 °C in buffer A. (JPEG 169 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2012